The prior art discloses a variety of methods and apparatus which can produce solid material directly from a source of molten material. Many of these prior art systems are for the fabrication of metal products and use some type of fixed, rigid, noncontrollable forming orifice to stabilize the dimensions of the product. Additionally, the prior art utilizes a wide variety of two wheel systems that form a kissing zone as they rotate in opposite directions.
With respect to two wheel systems which form a finished product, the Bessemer U.S. Pat. No. 49,053, discloses the basic, concept behind a majority of the systems that are currently utilized. Bessemer manufactures sheets, plates and the like directly from fluid malleable iron or steel by utilizing a pair of rolls, with their axes in a horizontal, parallel position to form a kissing zone. The molten metal is poured into this kissing zone, or thin space between the rolls, which are constantly moving during the flow of the metal between them. The cool surfaces of the rolls rapidly solidify the metal and the pressure of the rolls forms a metal product. However, as one would expect from such an early setup, there are many difficulties present in the system of Bessemer, particularly with respect to their utilization of a fixed sized crucible.
U.S. Pat. No. 1,756,196 to Hopkins, et al. discloses a method of making metal sheets wherein the method teaches solidifying on a first roll and then rolling with a second roll to produce a finished product.
U.S. Pat. No. 2,171,132 to Simons discloses a process of producing film products from molten materials in which a pair of relatively cool, rotating cylindrical members each have a portion of their surface submerged in the heated material. A suction process is utilized to suck the molten material in between the grooves on the wheel's outer surfaces.
U.S. Pat. No. 993,904 to Strange discloses a forerunner of a melt overflow system which is related to that used in the invention.
U.S. Pat. No. 4,224,978 to Klein discloses forming a metal strip product in a continuous casting process featuring two rolls and a kissing zone in which aluminum is discharged between the rolls by means of a nozzle having a particular structure; the process and apparatus are substantially different than those of the present invention.
U.S. Pat. No. 4,274,471 to Minoura, et al. discloses a process for the continuous casting of metals into sheets, wires, bars and the like. The process comprises a roll system with the main roll cooled from an inner portion and a plurality of sub-rolls, the sub-rolls being provided along the outer periphery surface of the main roll by holding a given gap against the main roll, supplying a molten metal into the gap formed by the main roll and the sub-rolls while rotating the main roll and the sub-rolls mutually in a direction carrying with the molten metal, allowing the molten metal to solidify when the molten metal passes through the gap between the main roll and the sub-rolls and taking out the solidified metal continuously from the roll system.
U.S. Pat. No. 4,518,029 to Shibuya, et al. discloses a double roll type method and apparatus for producing a thin metallic sheet by pouring a molten metal of a desired composition into a kissing region between two cooling rolls rotating in opposite directions, and rapidly cooling and solidifying the molten metal while it passes through the kissing region.
U.S. Pat. No. 4,705,905 discloses a textured surface which is suitable for usage as a cooling roll.
In page 45, FIG. 3 of the article, "Latest Developments and Operating Results of the High Speed Strip Coating Machine at SMS Schloemann-Siemag AG, W. Germany" by Friedrich-Marten et al., a two wheel strip caster is set forth.
It is known to utilize resiliently mounted springs on rotating wheels to control the resulting pressure exerted onto a sheet or film.
Accordingly, it is an object of the present invention to provide a process and accompanying apparatus which can produce a uniform, high quality film or sheet product of carefully controlled thinness, smoothness and microstructure by freezing material on one or both rolls followed by pressing the rolls to form either a unitary or a fused product.
It is another object of the invention to make a wide variety of film and sheet products by utilizing a single, flexible process and accompanying apparatus setup which can monitor the roll pressure in a roll kissing zone, be free of the problems involving metal orifices, have excellent control of the frozen film thickness and microstructure and be suitable for the utilization of textured rolls to make a product of desired characteristics.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.